This invention relates to a sealing shoe assembly for packaging machines which utilize wrapper sleeves (hose-like wrappers). The sealing shoe assembly has at least one pair of rotary sealing shoes provided with stamping (embossing) edges for forming a straight-line pattern of pressed-together areas in the face-to-face arranged portions of the wrapper sleeve.
In package making by means of wrapper sleeves, the incoming spaced articles to be packaged are introduced into the wrapper sleeves and subsequently the sleeves are closed and sealed by stamping (pressing-together) and the individual packages are separated from one another. The sealing shoe assemblies have face-to-face arranged stamping heads which are rotatably supported on the machine frame and which are well known in the packaging art.
U.S. Pat. No. 2,546,721 discloses a sealing shoe assembly which has two stamping heads mounted on cooperating rotary rolls. Each stamping head has elevations and depressions so designed that a waffle pattern is formed wherein the boundary lines form the elevations. It has been found that in case heavy wrapper material is used for the wrapper sleeve having longitudinal seams or pinch folds, the above-outlined stamped seal will be gas-tight only if the packing machine operates with a substantially reduced speed since, in particular, the sequence of the operational steps has to be coordinated with the required heat supply to the sealing shoes.